Certain classes of materials are known as semi-solids, examples of which are toothpastes, petroleum jellies, lip balms, and ointments. These particular examples are typically intended for personal use. They are commercially sold in squeezable containers, such as synthetic plastic or soft metal tubes for example, which are closed by a removable cap. Removing the cap exposes an opening through which the semi-solid inside the container can be forced out by squeezing the container. After a desired quantity of semi-solid has been squeezed out, the cap can be replaced to close the container.
A container may have a neck to which a removable cap is fitted, such as by a screw thread connection or a snap-on, snap-off connection. A cap may or may not be tethered to a container. Typical use of such a container involves a person holding the container in one hand and using the other hand to remove and replace the cap.